Dibutyl [[bis[(2-ethylhexyl)oxy]phosphinothioyl]thio]succinate

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

23 May 2006 to 30 May 2006

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

not specified

Specific details on test material used for the study:

Sample storage: room temperature

Analytical monitoring:

no

Remarks:

The investigation was carried out without accompanying analysis to check nominal concentrations.

Details on sampling:

Sample storage: room temperature

Vehicle:

no

Test organisms (species):

Daphnia magna

Details on test organisms:

Test organism: Daphnia magna, var. Straus,
Source: Dr. Knie LWA
Breeding: kept in drinking water at room temperature (20 +/- 1 °C) under diffuse lighting (16 hours a day); Young animals are separated daily, so that tested daphnia are not older than 24 hours and not younger than 6 hours
Feed: Daily with cells of Desmodesmus subspicatus

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test temperature:

20 +/- 1 °C

pH:

7.78 - 8.55

Dissolved oxygen:

6.8 - 8.9 mg O2/L

Nominal and measured concentrations:

100 mg/L (nominal)

Details on test conditions:

Static test over 48 hours, 4 parallel assays with each 5 animals per test item concentration

The daphnia were exposed to various test substance concentrations over 48 hours. Since the substance is difficult to dissolve in water, 100 mg of the substance were suspended in daphnia-dilution-water and shaken for 24 hours on the shaker at about 130 rpm before starting the test. It is presumed that during this time there is an equilibrium between water-soluble and water-insoluble part of the substance. After this incubation, the suspension was filtered through a glass fiber filter. The clear filtrate (eluate) was used directly without further dilution in the daphnia test. After 24 and 48 hours, the number of daphnia unable to swim was determined. pH value, water temperature and dissolved oxygen content were measured at the beginning and the end of the test.

Reference substance (positive control):

no

Duration:

24 h

Dose descriptor:

EC0

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

EC100

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

The investigation was carried out without accompanying analysis to check nominal concentrations.

The number of immobilized animals per parallel assay were determined after 24 and 48 hours.

Validity criteria fulfilled:

not specified

Conclusions:

No effects on mobilisation of daphnia were observed, resulting in an EC50 of greater than 100 mg/L under test conditions according to OECD Guideline 202.

Executive summary:

Daphnia toxicity of Butanedioic acid, [[bis(2-ethylhexyl)oxy]phosphinothioyl]thio]-, dibutylester was analyzed in a static limit test over 48 hours according to OECD guideline 202 (immobilisation test).

Since the substance is difficult to dissolve in water, 100 mg of the substance was suspended in daphnia-dilution-water and shaken for 24 hours on the shaker at about 130 rpm before starting the test. It was presumed that during this time there is an equilibrium between water-soluble and water-insoluble part of the substance. After this incubation, the suspension was filtered through a glass fiber filter. The clear filtrate (eluate) was used directly without further dilution in the daphnia test. After 24 and 48 hours, the number of daphnia unable to swim was determined. pH value, water temperature and dissolved oxygen content were measured at the beginning and and the end of the test. No effects on mobilisation of daphnia were observed, resulting in an EC50 of greater than 100 mg/L under test conditions according to OECD Guideline 202.

Description of key information

In an OECD 202 study, the acute toxicity of the test item to the freshwater invertebrate Daphnia magna was investigated under static conditions and the 48-hour EC50 value was determined to be greater than 100 mg/L loading rate WAF (SGS INSTITUT FRESENIUS GmbH, 2006).